Design of a monolithic dual-axis electrostatic actuation MEMS microgripper with capacitive position/force sensors

This paper presents the design of a new monolithic two-axis electrostatically actuated MEMS microgripper with integrated capacitive position and force sensors working at the micro-scale level. Each of the two jaws of the microgripper possesses two degree-of-freedom (DOF) and is capable of positioning in both x- and y-axes. Moreover, different from existing works where one gripper arm is actuated and other one is sensed, both arms of the proposed microgripper are actuated and sensed independently. A sensing scheme is then constructed to provide the position and force signals in the noncontact phase and contact phase, respectively. By applying a 120-V driving voltage, the jaw can provide 70 μm X direction and 18 μm Y direction displacements with the force of 190 μN. By this design, the real-time position and grasping force information can be obtained in the dual sensing mode. The performance of the designed microgripper is verified by both analytical modeling and finite-element analysis.